<template>
  <div>
    <div class="block">
      <el-tree
        ref="tree"
        :data="data"
        node-key="id"
        :default-expand-all="false"
        :props="defaultProps"
        :expand-on-click-node="false"
      >
        <span class="custom-tree-node" slot-scope="{ node, data }">
          <span>{{ node.label }}</span>
          <span>
            <el-button type="text" size="mini" @click="() => append(data)">
              Append
            </el-button>
            <el-button
              type="text"
              size="mini"
              @click="() => remove(node, data)"
            >
              Delete
            </el-button>
          </span>
        </span>
      </el-tree>
    </div>
  </div>
</template>

<script>
let id = 1000;

export default {
  data() {
    return {
      data: [
        {
          id: 1,
          label: "一级 1",
          children: [
            {
              id: 4,
              label: "二级 1-1",
              children: [
                {
                  id: 9,
                  label: "三级 1-1-1",
                },
                {
                  id: 10,
                  label: "三级 1-1-2",
                },
              ],
            },
          ],
        },
        {
          id: 2,
          label: "一级 2",
          children: [
            {
              id: 5,
              label: "二级 2-1",
            },
            {
              id: 6,
              label: "二级 2-2",
            },
          ],
        },
        {
          id: 3,
          label: "一级 3",
          children: [
            {
              id: 7,
              label: "二级 3-1",
            },
            {
              id: 8,
              label: "二级 3-2",
            },
          ],
        },
      ],
      defaultProps: {
        children: "children",
        label: "label",
      },
    };
  },
  methods: {
    append(data) {
      const newChild = { id: id++, label: "testtest", children: [] };
      if (!data.children) {
        this.$set(data, "children", []);
      }
      data.children.push(newChild);
    },
    // 当newChild的值变为了动态的，又应该怎么做呢

    remove(node, data) {
      const parent = node.parent;
      const children = parent.data.children || parent.data;
      const index = children.findIndex((d) => d.id === data.id);
      children.splice(index, 1);
    },
  },
};
</script>

<style scoped>
>>> .el-tree-node__content {
  display: flex;
  align-items: center;
  height: 2.354vw;
  border: 1px solid #eee;
  cursor: pointer;
}
>>> .el-tree-node__content {
  display: flex;
  align-items: center;
  height: 3.354vw;
  border: 1px solid #eee;
  cursor: pointer;
}
>>> .el-tree {
  height: calc(100vh - 260px);
  overflow-y: scroll;
}
</style>